To describe the maturation of cortico-cortical, commissural and cortico-subcortical connections in the developing primate; (2) To search for evidence of anomalous anatomical pathways resulting from early brain injury that would be capable of mediating behavioral recovery in the primate. Normal monkeys of various ages extending from birth through adulthood are given discrete unilateral injections of tritiated amino acids into the various areas of the cerebral cortex and sacrificed at appropriate intervals of time following surgery. Their brains are subsequently processed for anatomical analysis by silver impregnation or autoradiographic techniques. Monkeys that received bilateral orbital prefrontal lesions as infants and have demonstrated recovery of function at two years of age will be given unilateral lesions or injections of tritiated amino-acids in various regions of the brain hypothesized to be involved in mediating the recovery. BIBLIOGRAPHIC REFERENCES: Goldman, P.S., and Nauta, W.J.H.: An intricately patterned prefrontocaudate projection in the rhesus monkey. J. Comp. Neurol. 171: 369-386, 1977. Goldman, P.S., and Nauta, W.J.H.: Columnar distribution of cortico-cortical fibers in the frontal association, limbic and motor cortex of the developing rhesus monkey. Brain Research 122: 393-413, 1977.